Hardness prediction in multi-pass direct diode laser heat treatment by on-line surface temperature monitoring

Santhanakrishnan, Soundarapandian; Kovacevic, Radovan

doi:10.1016/j.jmatprotec.2012.06.002

Cited by 38 publications

(16 citation statements)

References 12 publications

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“…Specific tests used laser power from 1.4 kW to 1.8 kW and scanning speeds from 15 mm/s to 25 mm/s. The measured temperatures (infrared pyrometer and camera) were calibrated with the thermocouples and the results obtained showed a good agreement with an error less than 4% [15].…”

Section: Introductionmentioning

confidence: 84%

Effects of Laser Hardening Process Parameters on Case Depth of 4340 Steel Cylindrical Specimen—A Statistical Analysis

Barka

Ouafi

2015

JSEMAT

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Laser heat treatment is considered to be one of best-performing manufacturing processes used currently due to its flexibility and its ability to develop parts with complex geometries. In fact, this process is able to produce reliable parts with hard, thin martensite and compressive residual stresses. This paper explores the heat treatment applied to 4340 cylindrical parts heated using a Nd: Yag 3 kW laser source. In this case, the hardness profile is correlated to process parameters such as the laser source power, the beam scanning speed and the revolution speed of the part during heating. Based on preliminary tests stipulating that each parameter is varied alone within a specific range, a systematic design of final tests is performed using Taguchi matrix. The obtained results are analyzed using ANOVA method to extract the effects, the contributions and the interaction between the factors. The results are then exploited to study the sensitivity of the case depth according the variation of the process parameters. The developed model exhibits good potential for converging towards a robust model able to predict the hardness curve and to generalize it for other dimensions of cylindrical parts.

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Section: Introductionmentioning

confidence: 84%

Effects of Laser Hardening Process Parameters on Case Depth of 4340 Steel Cylindrical Specimen—A Statistical Analysis

Barka

Ouafi

2015

JSEMAT

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“…Selective control of surface material properties is also possible through laser processing. A high-power diode laser is often used in this type of surface modification process [18][19][20][21][22][23][24] because of its high metal absorptivity and typically rectangular beam shape (similar to a top hat in both directions), which allows for a larger treatment area than CO 2 [25], Nd:YAG [26], disks [27], and fiber lasers [28,29]. Therefore, the diode laser process is a strong candidate for the surface modification treatment of mold material used in the plastic injection process owing to its superior work efficiency compared to gas nitriding, plasma nitriding, plasma carburizing, chemical vapor deposition, ion beam treatment, and electron beam processes.…”

Section: Introductionmentioning

confidence: 99%

Microstructural Characterization of Surface Softening Behavior for Cu-Bearing Martensitic Steels after Laser Surface Heat Treatment

Chun

Sim

Kim

et al. 2018

Metals

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Abstract:The surface hardening and softening behavior of two types of medium carbon martensitic steel (AISI P20-improved and AISI P21) after laser-assisted heat treatment was quantitatively compared. The laser-assisted heat treatment was performed using a high-power diode laser with in situ temperature and laser power control (two-color pyrometer system). For AISI P20-improved steel, the peak hardness value within the hardening zone was approximately 640 HV after laser-assisted heat treatment at a temperature of 1473 K. In other words, the hardness increased by 120% from the base metal level (290 HV). However, for AISI P21 steel, the hardness within the heat-treated zone did not change from that of the base metal (410 HV), despite being accompanied by martensite transformation. Moreover, it was clearly observed that the hardness dropped below the level of the base metal at the boundary between the heat-treated zone and the base metal region, forming a softening zone. This softening behavior was strongly related to coarsening and a looser distribution of Cu precipitates compared with that of the base metal region, despite the same matrix phase (i.e., tempered martensite) existing in the softening zone and in the base metal region.

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“…LHT such as laser remelting, alloying or hardening from the solid state provides the possibility of modifying the microstructure and properties of local surface layers 40]. LHT can improve the hardness, wear and corrosive resistance of the surface layer.…”

Section: Introductionmentioning

confidence: 99%

“…Certainly, evaporation could also occur if the temperature exceeds the boiling point. It is worth emphasizing, that the temperature could be monitored using many thermometric techniques [39][40][41][42]. Pyrometry seems to be quite useful and simple method for surface temperature assessment during laser treatment [40][41][42].…”

Section: Introductionmentioning

confidence: 99%

The evaluation of the influence of laser treatment parameters on the type of thermal effects in the surface layer microstructure of gray irons

Paczkowska

2016

Optics & Laser Technology

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Hardness prediction in multi-pass direct diode laser heat treatment by on-line surface temperature monitoring

Cited by 38 publications

References 12 publications

Effects of Laser Hardening Process Parameters on Case Depth of 4340 Steel Cylindrical Specimen—A Statistical Analysis

Effects of Laser Hardening Process Parameters on Case Depth of 4340 Steel Cylindrical Specimen—A Statistical Analysis

Microstructural Characterization of Surface Softening Behavior for Cu-Bearing Martensitic Steels after Laser Surface Heat Treatment

The evaluation of the influence of laser treatment parameters on the type of thermal effects in the surface layer microstructure of gray irons

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